This application proposes that Stanford University Center for Female Urology and NeuroUrology participate as one of several National Clinical Centers in a cooperative effort to develop clinical trials for the study of interstitial cystitis (IC). The Principal Investigator intends to participate fully as a member of the steering committee in designing and carrying out multicenter randomized controlled clinical trials (RCTs). The investigative group at Stanford will work in parallel with the centers conducting trials for investigation of chronic prostatitis. A simultaneous application for that effort is being submitted. This is a critical juncture for IC research. While appreciation of the prevalence and impact of the disease is growing, little headway has been made in identifying the underlying etiology or finding reliably effective treatment. More importantly, the very definition of IC and pelvic pain syndromes is under active debate--are all patients with pelvic pain simply varying manifestations of a single underlying disorder or are there important clinical distinctions between IC, vulvadynia, chronic prostatitis, and pelvic floor dysfunction? The relevance of standard diagnostic tools has been challenged. Bladder distention under anesthesia may be neither sensitive nor specific. Neither urodynamic testing nor bladder biopsy provides specific diagnostic information. A simple office trial of intravesical potassium instillation purported to identify IC totally failed to predict response to therapy in a RCT. These and other critical issues will only be settled by carefully designed, large scale RCTs. The ICCRN should focus on the following specific aims: 1) determining the clinical utility of currently diagnostic tests for IC and evaluating new tests 2) developing evidence based algorithms for the work-up of IC patients involved in clinical research 3) developing relevant clinical protocols that involve the entire spectrum of IC patients 4) to test novel therapies for IC as they become available. Stanford is ideally suited for this project due to a long history of interest in IC, a Principal Investigator with recognized expertise in clinical research, an ethnically diverse patient base, and demonstrable success recruiting patients for IC research.